6. To isolate benzoic acid from a bicarbonate solution, it is acidified with concen- trated hydrochloric acid, as in experiment 1. What volume of acid is needed to neutralize the bicarbonate

For our assumed experiment; the expected  volume of Hcl acid needed to neutralize the bicarbonate is 0.13 mL

Explanation:

We are going attempt this question experimentally.

We know that benzoic acid originate from the relationship between  benzene and a carboxylic group. So basically , the functional group of a carboxylic acid (-COOH) joins with a benzene ring(C₆H₆) to form a simple aromatic carboxylic acid known as Benzoic acid. (C₇H₆O₂)

However, it is possible to isolate benzoic acid from  a bicarbonate solution in the presence of an acidified concentrated hydrochloric acid.

Let assume that ;

0.20 g of benzoic acid was reacted with 2 mL of a 20% solution of NaHCO₃, the amount of the  excess NaHCO₃ can be determined by subtracting the amount of benzoic acid from the amount of NaHCO₃.

Let first calculate the number of moles in 0.20 g of benzoic acid

we know that the standard  molar mass of benzoic acid is 122.12 g/mol

number of moles of benzoic acid = mass of benzoic acid/molar mass of benzoic acid =

number of moles of benzoic acid = 0.20/ 122.12

number of moles of benzoic acid = 0.0016 mol

number of moles of bicarbonate  solution = mass of bicarbonate solution/ molar mass of bicarbonate solution

number of moles of bicarbonate  solution =  0.2/84.00654 g/mol

number of moles of bicarbonate  solution =  0.00238 mol

∴

(0.00238 - 0.0016) mol

= 7.8 × 10⁻⁴ mol

Let assume that the concentrated HCl is 12  M

Also. HCl and NaHCO₃ react together at the ratio of 1:1; thus the  volume of Hcl acid needed to neutralize the bicarbonate is:

= 0.13 mL

Thus; for our assumed experiment; the expected  volume of Hcl acid needed to neutralize the bicarbonate is 0.13 mL

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

imma come back to you hold on